Print stops and asks to change filament multiple times during printing.  

RE: Print stops and asks to change filament multiple times during printing.

You have a dodgy install of he filament sensor in all likelihood.  It’s easy to test. Go into the printers lcd menu and turn off the filament sensor. Then do a short print. If there’s no issue then you know it’s the sensor. Although from your description it is almost certainly it. The symptoms are exactly right. The firmware process initiated for a colour change is the same routine used when a out of filament is triggered. 

Basically the sensor will need redoing to make it more reliable, you have to be very careful installing it and make sure there’s no burrs etc on the printed parts and it’s not too tight so the lever can freely move. 

RE: Print stops and asks to change filament multiple times during printing.

I will try that and post results.

Thanks Neophyl

RE: Print stops and asks to change filament multiple times during printing.

I have the same problem, but in the same point when my prusa work!
But the problem it's that not for the same gcode. the last two gcode that I made make the same mistake! ther's a setting on prusaslicer?
because I don't understand why whit one file don't do this and with the other one make this type of problem!

thanks all and thanks Zippy701 for the same question

RE: Print stops and asks to change filament multiple times during printing.

Gabik if you think its the gcode causing the problem just open it up with a text editor and look for M600 in there.  Thats the default colour change command.  Although yours doesnt sound the same as the original posters if it always happens at the same point.

Why you would have one in your sliced file unless you added one on the layer slider I don't know.  Unless you are using a profile downloaded from somewhere ?  Its quite possible to add in custom gcode to a profile that is always loaded.  Would need to see a saved project file (file >Save project as) from Prusa Slicer of one of the problem ones to know for sure.  If you do attach a 3mf file make sure to ZIP it up first or the forum wont accept the file type.  It needs zipping for anything beyond images or basic txt files.  

RE: Print stops and asks to change filament multiple times during printing.

That was it. you are a genius! Thanks again.

RE: Print stops and asks to change filament multiple times during printing.

Hi.

I have the same problem, but only when I am using Nonoilen filament from Fillamentum.

Is it possible that it is because of the settings that I use for this particular filament?

On early MK3's the filament sensor is purely optical and certain colours of filament, especially clear filaments, can cause false signals.

How old is your printer?

The workaround is to disable the sensor while printing that particular filament.

Cheerio,

RE: Print stops and asks to change filament multiple times during printing.

@neophyl thanks for the help. It worked for me too, do disable the filament sensor. If enabling the filament sensor again and the filament color is not the problem, what is the long term solution for this issue? 

Thanks

Posted by: @neophyl

You have a dodgy install of he filament sensor in all likelihood.  It’s easy to test. Go into the printers lcd menu and turn off the filament sensor. Then do a short print. If there’s no issue then you know it’s the sensor. Although from your description it is almost certainly it. The symptoms are exactly right. The firmware process initiated for a colour change is the same routine used when a out of filament is triggered. 

Basically the sensor will need redoing to make it more reliable, you have to be very careful installing it and make sure there’s no burrs etc on the printed parts and it’s not too tight so the lever can freely move. 

RE: Print stops and asks to change filament multiple times during printing.

I was having a similar problem. Cold pull was clean. This .gcode file is the same that I have used for years. The filament is the same - even the same roll that I used to successfully print 15 of these parts yesterday. Decided to do the firmware update (to 3.12.2, followed by the thermal model cal) this morning and was not able to complete a print afterwards. 

The print was stopping as if I had a color change within the file. Thought it odd at first then when it happened another two times during the same small print, looked in forums. I saw other comments about turning off the filament sensor which I did. During the next print it had clearly stopped extruding at the first "filament change point" but I was distracted and missed that it wasn't extruding. When I caught it, the nozzle was further up from the bed/partial print still "printing" then beeped and displayed "min bed temp fixed, please restart". I restarted and searched more. Found on another thread something about increasing idler tension. Tightened them slightly and the print has completed normally.  

Wanted to share in case anyone else continued to have problems after the filament sensor was turned off.

RE: Print stops and asks to change filament multiple times during printing.

I have another theory, it might be also because of the idler,

if the idler is too tense then the filament might be permanently squished by gears, if it happens and at some point extruder is doing bigger retraction it might be that this deformed part of the filament is going back to where the sensor is and is not being detected by that sensor because it's now thinner.

Why am I thinking that? I have a spool of a bit older black PLA that the printer is struggling with, but I decided to take advantage of those random filament swaps and insert some newer filament instead (middle layers won't be visible so I don't care about color). A newer spool of PLA filament works without struggle. TBH that old black PLA looks a bit weird and puffed, not sure how old is it, but compared to other PLAs I have 

MK3S+, I swapped firmware, models, cleaned up extruder internally from any dust - and it seems that last thing I did, filament swap, worked 

I haven't experiment with loosing up idler but that might be the answer too for such casese

RE: Print stops and asks to change filament multiple times during printing.

Thank you

This workaround worked for me.

RE: Print stops and asks to change filament multiple times during printing.

Hi, I'm having the same problem, but these methods don't seem to work in this case.

The 3D printer is actually owned by a friend. When they slice an STL file using PrusaSlicer 2.6.0, the GCode works OK. But when I slice it using PrusaSlicer 2.7.1 the GCode produces the fault described here where the printer stops after a short while and asks for the filament to be changed.

There are no M600 codes in the GCode. I did get my friend to produce a GCode file to compare with and the only significant differences are that the firmware version expected on the printer is different and the the E-coordinates throughout the file are different. I checked the settings files and there do not appear to be any differences between the settings.

Is there some difference between E-coordinates for different firmware versions or some revision made to their calculation in newer Slicer versions?

RE: Print stops and asks to change filament multiple times during printing.

I've also only had this issue on the latest version of the slicer. I'm currently downloading 2.6.1 again to see if that solves the issue.

RE: Print stops and asks to change filament multiple times during printing.

After testing with 2.6.1 the issue is resolved. I've submitted an issue on github which you can view here: https://github.com/prusa3d/PrusaSlicer/issues/12347

RE: Print stops and asks to change filament multiple times during printing.

Wow. Thank you so much even if your post was long ago... had the same issue because did not notice i accidentially added color changes on the layer-slider in PrusaSlicer! ...the icon is so small you don't even really realize its there if you are not aware. Maybe the Prusa guys could simply make the "+" icon bigger or move it a little farther away... 🙂

Cheers

FTE